Feathered drone mimics bird flight

A drone that uses retractable feather wings, mimicking the natural flight of birds, has been designed by researchers in Switzerland.

A drone inspired by bird wings has been designed by Swiss-based researchers, in an effort to make manouevring between buildings easy, while also increasing resistance to high winds.

The UAV's (unmanned aerial vehicle) wings are fitted with bird-like feathers, which its pilot can choose to spread or close during flight, via remote control. An autonomous version is currently under development.

The Swiss Federal Institute of Technology in Lausanne (EPFL) team, led by Professor Dario Floreano, observed birds in flight before creating their design.

Floreano was particularly interested in how birds' wings change shape, thanks to overlapping feathers and a joint at the end of both wings. This allows birds to fold back their primary flight feathers, significantly reducing the wings' surface area. Such an ability means birds can switch quickly from long, maneuverable wings that can turn and soar easily to short, stout wings optimised for speed.

Researcher Stefano Mintchev said no other drones have successfully managed to achieve both functions.

He told Reuters: "With conventional drones, since they have a fixed shape, their wings fly very efficiently in specific conditions, so they are designed, for example, to fly when there is high wind or to be very manouevrable, to perform tight turns in cluttered environments. These are opposing needs in a drone. The main advantage of our design is that we can combine both needs in a single platform thanks to the adaptive morphologies of the wing itself."

In nature, birds steer by spreading one wing and slightly retracting the other, creating a calculated imbalance that makes them turn.

The EPFL drone's feathers are made of lightweight composite materials, and fold and overlap like a fan, so the wings vary their surface area considerably.

"The most interesting part of this drone is these artificial feathers that are on the tip of the wings, and the main advantage is that we can achieve a reduction in surface of 50 percent and this is because the feathers overlap during the folding process," said Mintchev. "It's a very efficient technology to make wings that can change shape or the surface."

Mintchev says autonomous drones using the team's technology would be useful for delivery companies because they could move at speed between buildings. In addition, because they are foldable and easy to transport, they could be helpful in search and rescue missions

The research, which was funded by NCCR Robotics, was published in the Royal Society journal Interface Focus. — Reuters